/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:		arm_cmplx_dot_prod_f32.c
*
* Description:	Floating-point complex dot product
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup cmplx_dot_prod Complex Dot Product
 *
 * Computes the dot product of two complex vectors.
 * The vectors are multiplied element-by-element and then summed.
 *
 * The <code>pSrcA</code> points to the first complex input vector and
 * <code>pSrcB</code> points to the second complex input vector.
 * <code>numSamples</code> specifies the number of complex samples
 * and the data in each array is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * Each array has a total of <code>2*numSamples</code> values.
 *
 * The underlying algorithm is used:
 * <pre>
 * realResult=0;
 * imagResult=0;
 * for(n=0; n<numSamples; n++) {
 *     realResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+0] - pSrcA[(2*n)+1]*pSrcB[(2*n)+1];
 *     imagResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+1] + pSrcA[(2*n)+1]*pSrcB[(2*n)+0];
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_dot_prod
 * @{
 */

/**
 * @brief  Floating-point complex dot product
 * @param  *pSrcA points to the first input vector
 * @param  *pSrcB points to the second input vector
 * @param  numSamples number of complex samples in each vector
 * @param  *realResult real part of the result returned here
 * @param  *imagResult imaginary part of the result returned here
 * @return none.
 */

void arm_cmplx_dot_prod_f32(
    float32_t* pSrcA,
    float32_t* pSrcB,
    uint32_t numSamples,
    float32_t* realResult,
    float32_t* imagResult)
{
	float32_t real_sum = 0.0f, imag_sum = 0.0f;    /* Temporary result storage */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	uint32_t blkCnt;                               /* loop counter */

	/*loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
		real_sum += (*pSrcA++) * (*pSrcB++);
		/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
		imag_sum += (*pSrcA++) * (*pSrcB++);

		real_sum += (*pSrcA++) * (*pSrcB++);
		imag_sum += (*pSrcA++) * (*pSrcB++);

		real_sum += (*pSrcA++) * (*pSrcB++);
		imag_sum += (*pSrcA++) * (*pSrcB++);

		real_sum += (*pSrcA++) * (*pSrcB++);
		imag_sum += (*pSrcA++) * (*pSrcB++);

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

	while(blkCnt > 0u) {
		/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
		real_sum += (*pSrcA++) * (*pSrcB++);
		/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
		imag_sum += (*pSrcA++) * (*pSrcB++);


		/* Decrement the loop counter */
		blkCnt--;
	}

#else

	/* Run the below code for Cortex-M0 */

	while(numSamples > 0u) {
		/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
		real_sum += (*pSrcA++) * (*pSrcB++);
		/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
		imag_sum += (*pSrcA++) * (*pSrcB++);


		/* Decrement the loop counter */
		numSamples--;
	}

#endif /* #ifndef ARM_MATH_CM0 */

	/* Store the real and imaginary results in the destination buffers */
	*realResult = real_sum;
	*imagResult = imag_sum;
}

/**
 * @} end of cmplx_dot_prod group
 */
